Two-cylinder pump for heavy flowable materials, such as concrete

A two-cylinder pump for heavy flowable materials, such as concrete, comprising a shutter mechanism which is pivotable across an apertured face plate, the shutter mechanism being sealed against the face plate by means of a cutting ring which is axially movable relatively to the shutter mechanism and is supported thereon with its rear side engaging a rectangular cross-section flexible rubber ring which has first and second sides and first and second ends, the sides being of greater length than the ends whereby the cutting ring is urged resiliently against the face plate;

• a first cylindrical surface associated with the cutting ring and a second cylindrical surface associated with the shutter mechanism for locating the cutting ring, along a portion of its length, on the shutter mechanism;
• a support surface for engaging the first side of the flexible ring;
• a first seating for the first end of the flexible ring on the cutting ring which includes an annular extension which partly overlaps the second side of the flexible ring in the axial direction, a second seating for the second end of the flexible ring on the shutter mechanism which includes an annular extension which partly overlaps the second side of the flexible ring in the axial direction, said annular extensions partly overlapping the second side of the flexible ring from opposite ends thereof so that a part of the second side surface of the flexible ring is left free between the annular extensions, and stops on the cutting ring and the shutter mechanism which limit the extent of axial movement of the cutting ring in a direction away from the face plate.

A two-cylinder pump for heavy flowable materials, such as concrete, the pump comprising:

• an apertured face plate;
• a shutter mechanism which is pivotable across the apertured face plate, the shutter mechanism having a forward end spaced from and facing the face plate, a first annular flange which extends from the forward end axially toward the face plate, a second annular flange which extends radially from the forward end toward the face plate and which is generally parallel to the first annular flange, a generally radial shoulder surface between the first and second annular flanges, the first and second annular flanges and the radial shoulder surface defining an annular groove, a generally axial support surface associated with the first annular flange, and a generally radial stop surface;
• a cutting ring having a contact surface at a front end for contacting the face plate, a generally radial shoulder surface and an annular flange at a rear end, and a generally radial stop surface for engaging the stop surface of the shutter mechanism to limit axial movement of the cutting ring with respect to the shutter mechanism in an axial direction away from the face plate;
• a long stroke spring in the form of a flexible ring having a rectangular cross-section with first and second sides which are aligned generally axially and first and second ends which are aligned generally radially, the flexible ring being positioned between the shutter mechanism and the cutting ring for urging the contact surface of the cutting ring resiliently against the face plate, the first side of the flexible ring engaging the support surface of the shutter mechanism along essentially an entire length of the first side, the first end of the flexible ring being positioned in a first seating defined by the support surface of the shutter mechanism and the shoulder surface and the annular flange of the cutting ring so that the annular flange of the cutting ring partly overlaps the second side of the flexible ring in the axial direction, and the second end of the flexible ring being positioned in a second seating formed by the annular groove in the shutter mechanism so that the second flange of the shutter mechanism partly overlaps the second side of the flexible ring in the axial direction, the annular flange of the cutting ring and the second annular flange of the shutter mechanism being spaced from one another in the axial direction so that a part of the second side of the flexible ring is left free between the annular flange of the cutting ring and the second annular flange of the shutter mechanism.